DOCSLIB.ORG

Sphaeromyxids Form Part of a Diverse Group of Myxosporeans Infecting

Total Page：16

File Type：pdf, Size：1020Kb

Download full-text PDF Read full-text
Sphaeromyxids Form Part of a Diverse Group of Myxosporeans Infecting Kristmundsson and Freeman Parasites & Vectors 2013, 6:51 http://www.parasitesandvectors.com/content/6/1/51 RESEARCH Open Access Sphaeromyxids form part of a diverse group of myxosporeans infecting the hepatic biliary systems of a wide range of host organisms Árni Kristmundsson1 and Mark A Freeman2* Abstract Background: Approximately 40 species of Sphaeromyxa have been described, all of which are coelozoic parasites from gall bladders of marine fish. They are unique amongst the myxosporeans as they have polar filaments that are flat and folded instead of being tubular and spirally wound. This unusual feature was used as a subordinal character to erect the suborder Sphaeromyxina, which contains one family, the Sphaeromyxidae, and a single genus Sphaeromyxa. Methods: In the present study, we examine eelpout from the genus Lycodes from Iceland for the presence of myxosporean parasites in the gall bladder and perform morphological and DNA studies. Results: A novel myxosporean, Sphaeromyxa lycodi n. sp., was identified in the gall bladders of five of the six species of Lycodes examined, with a prevalence ranging from 29 - 100%. The coelozoic plasmodia are large, polysporous and contain disporic pansporoblasts and mature spores which are arcuate. The pyriform polar capsules encase long and irregularly folded ribbon-like polar filaments. Each spore valve has two distinct ends and an almost 180° twist along the relatively indistinct suture line. The single sporoplasm is granular with two nuclei. Sphaeromyxa lycodi is phylogenetically related to other arcuate sphaeromyxids and is reproducibly placed with all known sphaeromyxids and forms part of a robustly supported clade of numerous myxosporean genera which infect the hepatic biliary systems of a wide range of hosts. Conclusions: Sphaeromyxa lycodi is a common gall bladder myxosporean in eelpout of the genus Lycodes from Northern Iceland. It has characteristics typical of the genus and develops arcuate spores. Molecular phylogenetic analyses confirm that sphaeromyxids form a monophyletic group, subdivided into straight and arcuate spore forms, within the hepatic biliary clade that infect a wide range of freshwater associated animals. The ancestral spore form for the hepatic biliary clade was probably a Chloromyxum morphotype; however, sphaeromyxids have more recently evolved from an ancestor with a spindle-shaped Myxidium spore form. We recommend that the suborder Sphaeromyxina is suppressed; however, we retain the family Sphaeromyxidae and place it in the suborder Variisporina. Keywords: Sphaeromyxa, Lycodes, Gall bladder, Myxosporean, Myxidium, Hepatic biliary group, Chloromyxum Background There are approximately 40 species described from the Myxosporeans are common parasites of fish and have a genus Sphaeromyxa Thélohan 1892, all of which are two-host lifecycle involving an invertebrate that is gen- coelozoic parasites in gall bladders of marine fish and erally an annelid worm. The vertebrate host is typically form characteristic large flat plasmodia. Although not a fish but other aquatic-associated vertebrates such as usually associated with serious pathology, some may turtles, waterfowl and amphibians as well as terrestrial cause blockages of bile ducts which results in bile accu- insectivorous mammals are also reported as hosts [1-5]. mulation and liver inflammation [6]. Species of this genus are unusual in that they do not have a typical tube-like polar filament that is spirally wound in the * Correspondence: [email protected] 2Institute of Ocean and Earth Sciences, University of Malaya, Kuala Lumpur polar capsule. Rather, it is flat in section, broad at the 50603, Malaysia base, gradually tapering along its length and is folded Full list of author information is available at the end of the article © 2013 Kristmundsson and Freeman; licensee BioMed Central Ltd. This is an Open Access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/2.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. Kristmundsson and Freeman Parasites & Vectors 2013, 6:51 Page 2 of 13 http://www.parasitesandvectors.com/content/6/1/51 upon itself several times in the polar capsule. Lom and range 43 – 62 cm: n = 10), L. gracilis(18– 27 cm; n = 21), Noble [7] proposed this unusual feature as a new subor- L. reticulatus (11 – 23 cm; n = 22), L. pallidus (18 – 26 dinal character and erected the suborder Sphaeromyxina cm; n = 4), L. seminudus (16 – 36 cm; n = 10) and L. Lom et Noble, 1984 to include a single new family eudipleurostictus (10 – 29 cm; n = 22). Immediately after Sphaeromyxidae Lom et Noble, 1984. In Thélohan’s ori- catching, the fish were frozen aboard the research vessel. ginal description of the genus, Sphaeromyxa, he consid- After the survey the fish were taken to a laboratory and ered it to be a member of the family Myxidiidae Thelohan kept frozen until examination. 1892. DNA sequence data for sphaeromyxids are some- what limited, with information available for only 5 species. However, currently they are one of the few monophyletic Fresh material - spore measurements myxosporean taxa [8] and unusually group with a range of Thawed fish were dissected, their gall bladder removed other myxosporean genera that infect the gall bladders of and a drop of its contents put on a microscopic slide and freshwater hosts [9]. screened for the presence of myxosporean infections at a There are few reports of myxosporeans from eelpout magnifications of 200× - 400×. Initially two species of fish (Zoarcidae). The type species of the genus Shulmania, S. were chosen, L. reticulatus and L. eudipleurostictus,and ovale, was described from the urinary bladder of Lycodes descriptions and measurements of spores were taken fol- esmarkii from the Canadian Atlantic [10]. In the Pacific, lowing the guidelines of Lom and Arthur [13]. Fresh Myxidium melanostigmum was described from the gall spores were measured and photographed using bright field bladder of the eelpout Melanostigma pammelas adeepwa- and Nomarski illumination at magnification up to 1250×. ter fish off the Californian coast [11] and Myxobolus All other fish species were checked for the presence of aeglefini was found in the skeletal muscle of porous-head myxosporeans and samples taken for DNA analyses. eelpout Allolepis hollandi from the Sea of Japan [12]. In the present study, we examine eelpout, from the genus Histology Lycodes, from Iceland for the presence of myxosporean Gall bladders from two infected fish, one L. reticulatus parasites in the gall bladder. and one L. eudipleurostictus, were fixed in 10% buffered formalin, embedded in paraffin wax, sectioned (4 μm), Methods stained with Giemsa and Haematoxylin and Eosin and Fish were sampled by trawling (300 – 500 m) north of prepared for histological examination according to routine Iceland in July 2012 during an annual survey performed protocols. In addition, air dried smears from infected gall by the Marine Research Institute in Iceland (Figure 1). bladders were fixed in methanol and stained with Giemsa These included adult fish of Lycodes esmarkii (length and Haematoxylin and Eosin. 67°18´N 21°44´W 67°10´N 15°51´W 66°26´N 18°33´W Iceland Figure 1 Sampling area of Lycodes spp. north of Iceland (shaded area) demarcated by three coordinates. Kristmundsson and Freeman Parasites & Vectors 2013, 6:51 Page 3 of 13 http://www.parasitesandvectors.com/content/6/1/51 SEM methods adjusted manually to achieve optimum alignments. The The contents of an infected gall bladder from each spe- final alignment was manually edited using the BioEdit cies (L. reticulatus and L. eudipleurostictus)ofhostfish sequence alignment editor and contained 2619 charac- were fixed in 2.5% glutaraldehyde for 4 hrs at 4°C, and ters of which 1358 were informative sites. then rinsed four times in 100 mM sodium cacodylate Phylogenetic analyses were performed using the max- buffer pH 7.2 allowing the spores to settle under gravity imum likelihood methodology in PhyML [18] with the between each rinse. The resulting spore suspension was general time-reversible substitution model selected and W passed through a 0.4 μm Whatman Cyclopore track- 100 bootstrap repeats. Maximum parsimony in PAUP*4.0 etched polycarbonate membrane using a syringe and beta10 [19] using a heuristic search with random taxa filter clamp. The membrane was then post-fixed in 1% addition (10 replications), the ACCTRAN-option, and the osmium tetroxide in 100 mM sodium cacodylate buffer TBR swapping algorithm with gaps treated as missing data pH 7.2 for 2hrs and taken through an ethanol series of and branch supports obtained with 1000 bootstrap rep- 30%, 60%, 90% and 2 × 100% 30 mins each, transferred licates. Bayesian inference (BI) analysis using MrBayes into 50% hexamethyldisilazane (HMDS) in 100% ethanol v. 3.2.1 [20]. The BI analysis models of nucleotide sub- followed by two changes of 100% HMDS each for 45 min. stitution were first evaluated for the alignment using Excess HMDS was removed and the membranes allowed MrModeltest v. 2.2 [21]. The most parameter-rich to air dry overnight. The membranes were then mounted evolutionary model based on the AIC was the general onto aluminium stubs, earthed with silver dag paint and time-reversible, GTR+I+G model of evolution. Therefore, sputter-coated with gold. Samples were viewed with a Jeol the settings used for the analysis were nst = 6, with the JSM 6460 LV SEM instrument. gamma- distributed rate variation across sites and a pro- portion of invariable sites (rates = invgamma). The priors DNA analysis on state frequency were left at the default setting (Prset Gall bladder contents from three infected fish from, L. statefreqpr = dirichlet (1, 1, 1, 1)). Posterior probability reticulatus and L. eudipleurostictus, were used in initial distributions were generated using the Markov Chain DNA extractions and to obtain the majority (18e-18gM) Monte Carlo (MCMC) method with four chains being run of the small subunit ribosomal DNA (SSU rDNA) se- simultaneously for 1000,000 generations.
Load more

Recommended publications
  • History of Myxozoan Character Evolution on the Basis of Rdna and EF-2 Data Ivan Fiala1,2*, Pavla Bartošová1,2
    Fiala and Bartošová BMC Evolutionary Biology 2010, 10:228 http://www.biomedcentral.com/1471-2148/10/228 RESEARCH ARTICLE Open Access History of myxozoan character evolution on the basis of rDNA and EF-2 data Ivan Fiala1,2*, Pavla Bartošová1,2 Abstract Background: Phylogenetic relationships among myxosporeans based on ribosomal DNA data disagree with traditional taxonomic classification: a number of myxosporeans with very similar spore morphology are assigned to the same genera even though they are phylogenetically distantly related. The credibility of rDNA as a suitable marker for Myxozoa is uncertain and needs to be proved. Furthermore, we need to know the history of myxospore evolution to understand the great diversity of modern species. Results: Phylogenetic analysis of elongation factor 2 supports the ribosomal DNA-based reconstruction of myxozoan evolution. We propose that SSU rDNA is a reliable marker for inferring myxozoan relationships, even though SSU rDNA analysis markedly disagrees with the current taxonomy. The analyses of character evolution of 15 morphological and 5 bionomical characters show the evolution of individual characters and uncover the main evolutionary changes in the myxosporean spore morphology and bionomy. Most bionomical and several morphological characters were found to be congruent with the phylogeny. The summary of character analyses leads to the simulation of myxozoan ancestral morphotypes and their evolution to the current species. As such, the ancestor of all myxozoans appears to have infected the renal tubules of freshwater fish, was sphaerosporid in shape, and had a spore with polar capsules that discharged slightly sideways. After the separation of Malacosporea, the spore of the common myxosporean ancestor then changed to the typical sphaerosporid morphotype.
    [Show full text]
  • A New Species of Myxidium (Myxosporea: Myxidiidae)
    University of Nebraska - Lincoln DigitalCommons@University of Nebraska - Lincoln John Janovy Publications Papers in the Biological Sciences 6-2006 A New Species of Myxidium (Myxosporea: Myxidiidae), from the Western Chorus Frog, Pseudacris triseriata triseriata, and Blanchard's Cricket Frog, Acris crepitans blanchardi (Hylidae), from Eastern Nebraska: Morphology, Phylogeny, and Critical Comments on Amphibian Myxidium Taxonomy Miloslav Jirků University of Veterinary and Pharmaceutical Sciences, Palackého, [email protected] Matthew G. Bolek Oklahoma State University, [email protected] Christopher M. Whipps Oregon State University John J. Janovy Jr. University of Nebraska - Lincoln, [email protected] Mike L. Kent OrFollowegon this State and Univ additionalersity works at: https://digitalcommons.unl.edu/bioscijanovy Part of the Parasitology Commons See next page for additional authors Jirků, Miloslav; Bolek, Matthew G.; Whipps, Christopher M.; Janovy, John J. Jr.; Kent, Mike L.; and Modrý, David, "A New Species of Myxidium (Myxosporea: Myxidiidae), from the Western Chorus Frog, Pseudacris triseriata triseriata, and Blanchard's Cricket Frog, Acris crepitans blanchardi (Hylidae), from Eastern Nebraska: Morphology, Phylogeny, and Critical Comments on Amphibian Myxidium Taxonomy" (2006). John Janovy Publications. 60. https://digitalcommons.unl.edu/bioscijanovy/60 This Article is brought to you for free and open access by the Papers in the Biological Sciences at DigitalCommons@University of Nebraska - Lincoln. It has been accepted for inclusion in John Janovy Publications by an authorized administrator of DigitalCommons@University of Nebraska - Lincoln. Authors Miloslav Jirků, Matthew G. Bolek, Christopher M. Whipps, John J. Janovy Jr., Mike L. Kent, and David Modrý This article is available at DigitalCommons@University of Nebraska - Lincoln: https://digitalcommons.unl.edu/ bioscijanovy/60 J.
    [Show full text]
  • CNIDARIA Corals, Medusae, Hydroids, Myxozoans
    FOUR Phylum CNIDARIA corals, medusae, hydroids, myxozoans STEPHEN D. CAIRNS, LISA-ANN GERSHWIN, FRED J. BROOK, PHILIP PUGH, ELLIOT W. Dawson, OscaR OcaÑA V., WILLEM VERvooRT, GARY WILLIAMS, JEANETTE E. Watson, DENNIS M. OPREsko, PETER SCHUCHERT, P. MICHAEL HINE, DENNIS P. GORDON, HAMISH J. CAMPBELL, ANTHONY J. WRIGHT, JUAN A. SÁNCHEZ, DAPHNE G. FAUTIN his ancient phylum of mostly marine organisms is best known for its contribution to geomorphological features, forming thousands of square Tkilometres of coral reefs in warm tropical waters. Their fossil remains contribute to some limestones. Cnidarians are also significant components of the plankton, where large medusae – popularly called jellyfish – and colonial forms like Portuguese man-of-war and stringy siphonophores prey on other organisms including small fish. Some of these species are justly feared by humans for their stings, which in some cases can be fatal. Certainly, most New Zealanders will have encountered cnidarians when rambling along beaches and fossicking in rock pools where sea anemones and diminutive bushy hydroids abound. In New Zealand’s fiords and in deeper water on seamounts, black corals and branching gorgonians can form veritable trees five metres high or more. In contrast, inland inhabitants of continental landmasses who have never, or rarely, seen an ocean or visited a seashore can hardly be impressed with the Cnidaria as a phylum – freshwater cnidarians are relatively few, restricted to tiny hydras, the branching hydroid Cordylophora, and rare medusae. Worldwide, there are about 10,000 described species, with perhaps half as many again undescribed. All cnidarians have nettle cells known as nematocysts (or cnidae – from the Greek, knide, a nettle), extraordinarily complex structures that are effectively invaginated coiled tubes within a cell.
    [Show full text]
  • Disease of Aquatic Organisms 89:209
    Vol. 89: 209–221, 2010 DISEASES OF AQUATIC ORGANISMS Published April 9 doi: 10.3354/dao02202 Dis Aquat Org OPEN ACCESS Light and electron microscopic studies on turbot Psetta maxima infected with Enteromyxum scophthalmi: histopathology of turbot enteromyxosis R. Bermúdez1,*, A. P. Losada2, S. Vázquez2, M. J. Redondo3, P. Álvarez-Pellitero3, M. I. Quiroga2 1Departamento de Anatomía y Producción Animal and 2Departamento de Ciencias Clínicas Veterinarias, Facultad de Veterinaria, Universidad de Santiago de Compostela, 27002 Lugo, Spain 3Instituto de Acuicultura de Torre la Sal, Consejo Superior de Investigaciones Científicas, 12595 Ribera de Cabanes, Castellón, Spain ABSTRACT: In the last decade, a new parasite that causes severe losses has been detected in farmed turbot Psetta maxima (L.), in north-western Spain. The parasite was classified as a myxosporean and named Enteromyxum scophthalmi. The aim of this study was to characterize the main histological changes that occur in E. scophthalmi-infected turbot. The parasite provoked catarrhal enteritis, and the intensity of the lesions was correlated with the progression of the infection and with the develop- ment of the parasite. Infected fish were classified into 3 groups, according to the lesional degree they showed (slight, moderate and severe infections). In fish with slight infections, early parasitic stages were observed populating the epithelial lining of the digestive tract, without eliciting an evident host response. As the disease progressed, catarrhal enteritis was observed, the digestive epithelium showed a typical scalloped shape and the number of both goblet and rodlet cells was increased. Fish with severe infections suffered desquamation of the epithelium, with the subsequent release of par- asitic forms to the lumen.
    [Show full text]
  • Myxidium Shedkoae Sokolov, 2013 (Myxozoa: Myxidiidae), A
    Acta Veterinaria Hungarica 66 (2), pp. 258–268 (2018) DOI: 10.1556/004.2018.024 MYXIDIUM SHEDKOAE SOKOLOV, 2013 (MYXOZOA: MYXIDIIDAE), A PARASITE OF THE GALLBLADDER OF PERCCOTTUS GLENII DYBOWSKI, 1877 (ACTINOPTRYGII: ODONTOBUTIDAE): SUPPLEMENTARY DATA ON MORPHOLOGY AND PHYLOGENETIC POSITION BASED ON 18S rDNA SEQUENCE ANALYSIS 1,2 2* Sergey SOKOLOV and Daria LEBEDEVA 1A. N. Severtsov Institute of Ecology and Evolution, Russian Academy of Sciences; 2Institute of Biology of Karelian Research Center, Russian Academy of Sciences, 11 ul. Pushkinskaya, 185910 Petrozavodsk, Russia (Received 17 January 2018; accepted 16 April 2018) This paper is the first report on the molecular characterisation of myxozo- an parasites from the odontobutid fish Chinese (Amur) sleeper (Perccottus glenii Dybowski, 1877). The authors determined the partial 18S rDNA sequence of Myxidium shedkoae Sokolov, 2013 from the gallbladder of the fish. Phylogenies reconstructed using maximum likelihood and Bayesian inference analysis re- vealed that M. shedkoae belongs to the hepatic biliary group of myxozoans (after Kristmundsson and Freeman, 2013) as a member of the clade consisting of Zschokkella sp. KLT-2014, Myxidium truttae and Zschokkella nova. Some new morphological features of the parasite are also presented. Key words: Myxozoa, Myxidium shedkoae, Perccottus glenii, Chinese sleeper, odontobutid fish, phylogeny The genus Myxidium Bütschli, 1882 comprises more than 200 species of myxozoans parasitic in kidneys, urinary and biliary tracts mostly of freshwater and marine fishes, but also amphibians, reptiles and birds (e. g. Eiras et al., 2011). As a rule, the genus Myxidium includes species with linear or slightly curved fu- siform spores. The spores have one more or less pyriform polar capsule at each end with a binucleate sporoplasm between the polar capsules.
    [Show full text]
  • Description of Three New Species of Myxosporidia (Cnidaria
    Aquacu OPEN ACCESS Freely available online nd ltu a r e s e J i o r u e r h n s a i l F Fisheries and Aquaculture Journal ISSN: 2150-3508 Research Article Description of Three New Species of Myxosporidia (Cnidaria: Myxobolidae) Parasites of Paramormyrops kingsleyae Günther, 1896 (Mormyridae) in the Nyong Basin in Cameroon Lekeufack Folefack Guy Benoît1*, Fongang Tsekeng Charlotte Vanessa2, Fomena Abraham1 1Department of Animal Biology and Physiology, Laboratory of Parasitology and Ecology, University of Yaounde I, P.O. Box 812, Yaounde, Cameroon; 2Higher Teacher’s Training College, Laboratory of Zoology, University of Yaounde I, P.O. Box 47, Yaounde, Cameroon ABSTRACT Parasitological examination of Paramormyrops kingsleyae Günther, 1896 caught in the Djolon River in Cameroon revealed the presence of three new species of Myxosporidia of the genus Myxidium Bütschli 1882 and Henneguya Thelohan, 1892 of which complete description is given in the present study. These species are: Myxidium binguelai sp. nov., parasite of the kidney that produce fusiform spores with a turgid medial part and both ends pointed. They measured 12.1 (11.1-12.9) µm long x 5.3 (4.8-5.8) µm broad; the polar capsules are ovoid, equal in size and measure 3.6 (3.0-4.1) µm x 2.5 (2.0-2.8) µm. Myxidium djolonensis sp. nov., a parasite of the gall bladder and urinary bladder, produce fusiform and elongated spores, that measure 16.3 (15.5-18.0) µm long x 6.1 (5-7.1) µm broad; its polar capsules are equal and measure 4.9 (4-5.6) x 3.5 (3-4.2) µm.
    [Show full text]
  • Full Text in Pdf Format
    Vol. 141: 39–46, 2020 DISEASES OF AQUATIC ORGANISMS Published online September 17 https://doi.org/10.3354/dao03514 Dis Aquat Org Morphological, histological and molecular characterization of Myxidium cf. rhodei infecting the kidney of Rutilus rutilus Marina Dashi-Dorjievna Batueva1,#, Xiaoyi Pan2,#, Jinyong Zhang3,4, Xinhua Liu3, Wu Wei3, Yang Liu3,4,* 1Institute of General and Experimental Biology of the Siberian Branch of the Russian Academy of Sciences, 670047 Ulan-Ude, Russia 2Key Laboratory of Healthy Freshwater Aquaculture, Ministry of Agriculture and Rural Affairs; Key Laboratory of Fish Health and Nutrition of Zhejiang Province, Zhejiang Institute of Freshwater Fisheries, 313001 Huzhou, PR China 3Key Laboratory of Aquaculture Diseases Control, Ministry of Agriculture and Rural Affairs; State Key Laboratory of Freshwater Ecology and Biotechnology, Institute of Hydrobiology, Chinese Academy of Sciences, 430072 Wuhan, PR China 4School of Marine Science and Engineering, Qingdao Agricultural University, 266109 Qingdao, PR China ABSTRACT: In the present study, we provide supplementary data for Myxidium cf. rhodei Léger, 1905 based on morphological, histological and molecular characterization. M. cf. rhodei was ob - served in the kidneys of 918 out of 942 (97%) roach Rutilus rutilus (Linnaeus, 1758). Myxospores of M. cf. rhodei were fusiform with pointed ends, measuring 12.7 ± 0.1 SD (11.8−13.4) μm in length and 4.6 ± 0.1 (3.8−5.4) μm in width. Two similar pear-shaped polar capsules were positioned at either ends of the longitudinal axis of the myxospore: each of these capsules measured 4.0 ± 0.1 (3.1−4.7) μm in length and 2.8 ± 0.1 (2.0−4.0) μm in width.
    [Show full text]
  • Development of the Marine Myxozoan, Kudoa Thyrsites
    DEVELOPMENT OF THE MARINE MYXOZOAN, KUDOA THYRSITES (GILCHRIST, 1924), IN NETPEN-REARED ATLANTIC SALMON (SU0 SAUR L.) IN BRlTISH COLUMBIA Jonathan David William Moran B-Sc., University of New Brunswick (Fredericton), 1992 M-Sc., University of New Brunswick (Fredericton), 1994 A THESIS SUBMIïTED IN PARTIAL FULFILLMENT OF THE REQUIREMENTS FOR THE DEGREE OF DOCTOR OF PHILOSOPHY in the Department of Biological Sciences O Jonathan D.W. Moran 1999 SIMON FRASER UNIVERSITY May 1999 Al1 rights resewed. This work rnay not be reproduced in whole or in part, by photocopy or other means, without permission of the author. National Library Bibliothèque nationale 1*1 of Canada du Canada Acquisitions and Acquisitions et Bibliographie Services services bibliographiques 395 Wellington Street 395. me WeHingtm OttawaON K1A ON4 OcrawaON KiA OF)4 Canada Canada The author has granted a non- L'auteur a accordé une licence non exclusive Licence aliowing the exclusive permettant à la National Libras, of Canada to Bibliothèque nationale du Canada de reproduce, loan, distribute or seii reproduire, prêter, distribuer ou copies of this thesis in microfom, vendre des copies de cette thèse sous paper or electronic formats. la forme de microfiche/film, de reproduction sur papier ou sur format électronique. The author retains ownership of the L'auteur conserve la propriété du copyright in this thesis. Neither the droit d'auteur qui protège cette thèse. thesis nor substantial extracts fiom it Ni Is thkse ni des extraits substantiels may be printed or othenvise de celle-ci ne doivent être imprimés reproduced without the author' s ou autrement reproduits sans son permission.
    [Show full text]
  • Disease of Aquatic Organisms 80:199
    Vol. 80: 199–209, 2008 DISEASES OF AQUATIC ORGANISMS Published August 7 doi: 10.3354/dao01912 Dis Aquat Org Myxidium scripta n. sp. identified in urinary and biliary tract of Louisiana-farmed red-eared slider turtles Trachemys scripta elegans John F. Roberts1, 5,*, Christopher M. Whipps4, 6, Jerri L. Bartholomew4, Lynda Schneider2, Elliott R. Jacobson3 1Department of Infectious Disease and Pathology, College of Veterinary Medicine; 2The Electron Microscopy Core Laboratory, Biotechnology Program; 3Department of Small Animal Clinical Sciences, College of Veterinary Medicine; University of Florida, Gainesville, Florida 32610, USA 4Center for Fish Disease Research, Department of Microbiology, Oregon State University, Corvallis, Oregon 97331, USA 5Present address: Thompson-Bishop-Sparks State Diagnostic Laboratory, PO Box 2209, Auburn, Alabama 36831, USA 6Present address: Environmental and Forest Biology, State University of New York College of Environmental Science and Forestry, Syracuse, New York 13210, USA ABSTRACT: During a necropsy investigation of a mortality event occurring at a turtle farm in Assumption Parish, Louisiana, spores of a myxozoan were identified in the renal tubules in 3 of 6, the gall bladder lumen in 2 of 6, and the bile ductule in 1 of 6 red eared slider turtles Trachemys scripta elegans. In total, myxozoa were identified in 4 of 6 turtles. In 1 turtle, renal tubules contained numer- ous mature spores, had epithelial hyperplasia, granulomatous transformation, compression of adja- cent tubules and interstitial lymphocytic nephritis. The genus of myxozoan was Myxidium, based on spore morphology in cytological preparations, in histologic section, and by electron microscopy. In cytological preparation the spores had mean dimensions of 18.8 × 5.1 µm and a mean polar capsule dimension of 6.6 × 3.5 µm.
    [Show full text]
  • Disease of Aquatic Organisms 133:99
    Vol. 133: 99–105, 2019 DISEASES OF AQUATIC ORGANISMS Published online February 28 https://doi.org/10.3354/dao03335 Dis Aquat Org OPENPEN ACCESSCCESS Host size influences prevalence and severity of Kudoa thyrsites (Cnidaria: Myxosporea) infection in Atlantic salmon Salmo salar Simon R. M. Jones*, Amy Long Pacific Biological Station, 3190 Hammond Bay Road, Nanaimo, British Columbia, V9T 6N7, Canada ABSTRACT: Kudoa thyrsites is a cosmopolitan myxozoan parasite of marine fish. The infection causes an economically important myoliquefaction in farmed Atlantic salmon in British Columbia, Canada. Laboratory exposure of Atlantic salmon smolts to infectious seawater was used to test the hypothesis that infection with K. thyrsites is more severe in age-matched, smaller salmon. In each of 2 trials approximately 4 mo apart, smolts were graded into small (80 and 68 g), medium (117 and 100 g) and large (142 and 157 g) initial weight groups (IWGs) and concurrently exposed to infec- tious seawater. The effects of IWG and time on fish size and infection severity were assessed by linear mixed-effects models. The fish were screened for infection by histological examination at intervals following exposure. Increases in mean length and weight were statistically significant in all IWG during both trials. The infection was detected in fish in both trials, and in Trial 2, the prevalence was significantly greater in larger fish 1000 degree-days (DD) after exposure. The severity of infection (plasmodia mm−2 muscle) was significantly higher in larger smolts: between medium and large IWGs at 2500 DD in Trial 1 and between small and medium IWGs at 1500 and 2000 DD in Trial 2.
    [Show full text]
  • Myxosporean Parasites in Australian Frogs and Tadpoles
    Myxosporean Parasites in Australian Frogs and Tadpoles Ashlie Hartigan B Sc. (Zoology), M App Sci (Wildlife Health and Pop. Mgmt) Thesis by published works This thesis is submitted in full satisfaction of the requirements for the degree of Doctor of Philosophy at the University of Sydney. Faculty of Veterinary Science University of Sydney March 2012 Statement of authentication This thesis is submitted to the University of Sydney in fulfilment of the requirement for the degree of Doctor of Philosophy. The work presented in this thesis is, to the best of my knowledge and belief, original except as acknowledged in the text. I hereby declare that I have not submitted this material, either in full or in part, for a degree at this or any other institution. Signed: Date: ii Abstract The investigation of new threats to amphibian conservation is a priority of researchers and wildlife managers. Emerging infectious diseases are one of the most threatening processes to wildlife around the world including amphibians. Australian frogs have suffered large scale declines and extinctions from pathogens such as chytrid fungus (Batrochochytrium dendrobatidis). The once overly abundant Green and golden bell frog (Litoria aurea) has declined over 90% of its range with disease listed as a key threat. A routine pathogen screen of tadpoles from a captive breeding population of Green and golden bell frogs found an unknown parasitic infection in the brains, bile ducts and gallbladders of tadpoles (later confirmed as Myxosporea). It was this preliminary identification that was the impetus for my thesis. Myxosporean parasites found in Australian frog gallbladders were thought to be Cystodiscus immersus from Central and South America.
    [Show full text]
  • PREVALENCE of Kudoa Thyrsites in PACIFIC HAKE (Merluccius Productus) and THERMAL RESISTANCE of Kudoa Thyrsites and Kudoa Paniformis SPORES
    PREVALENCE OF Kudoa thyrsites IN PACIFIC HAKE (Merluccius productus) AND THERMAL RESISTANCE OF Kudoa thyrsites AND Kudoa paniformis SPORES by GRACE TAMKEE B. Sc. (Agr.), The University of British Columbia, 1999 A THESIS SUBMITTED IN PARTIAL FULFILLMENT OF THE REQUIREMENTS FOR THE DEGREE OF MASTER OF SCIENCE in THE FACULTY OF GRADUATE STUDIES (Food Science Programme). We accepUhis thesis as conforming tO/theVequired standard THE UNIVERSITY OF BRITISH COLUMBIA October 2003 © Grace Tamkee, 2003 In presenting this thesis in partial fulfilment of the requirements for an advanced degree at the University of British Columbia, I agree that the Library shall make it freely available for reference and study. I further agree that permission for extensive copying of this thesis for scholarly purposes may be granted by the head of my department or by his or her representatives. It is understood that copying or publication of this thesis for financial gain shall not be allowed without my written permission. Department of The University of British Columbia Vancouver, Canada Date QdfllflJg^ (ffi , 200^ DE-6 (2/88) Abstract Experiments were conducted to determine the potential of Pacific hake (Merluccius productus) fish meal to act as a vector of Kudoa thyrsites transmission to farmed Atlantic salmon (Salmo salar). This was done by determining the prevalence and intensity of K. thyrsites in Pacific hake destined for fish meal processing, developing a viability test for K. thyrsites, and determining the thermal resistance of K. thyrsites. Thermal resistance experiments were also performed for K. paniformis. Pacific hake samples were collected from the rendering plant in 2001 and 2002.
    [Show full text]